HEMODYNAMIC-RESPONSES AND ADVERSE-EFFECTS ASSOCIATED WITH ADENOSINE AND DIPYRIDAMOLE PHARMACOLOGICAL STRESS-TESTING - A COMPARISON IN 2,000PATIENTS

Objective: To compare the hemodynamic responses and the adverse effect s associated with two coronary vasodilators used for pharmacologic str ess testing. Design: We retrospectively studied the results of adenosi ne and dipyridamole perfusion imaging in a large group of patients who underwent pharmacologic stress radionuclide perfusion imaging. Materi al and Methods: One thousand patients given dipyridamole between April 1989 and April 1991 (before adenosine became available) were compared with 1,000 patients given adenosine between April 1991 and October 19 92. A standard protocol was used to infuse the drugs before myocardial perfusion imaging with Tl-201 or Tc-99m sestamibi. Results: Peak hear t rate was higher (85 versus 83 beats/min; P = 0.02) and systolic bloo d pressure was lower (129 versus 133 mm Hg; P<0.0001) with adenosine t han with dipyridamole. More patients had a decrease in systolic blood pressure of 30 mm Hg or more with adenosine than with dipyridamole (P = 0.002), Horizontal or downsloping ST-segment depression of 1 mm or m ore occurred in 9% of patients who received adenosine and in 8% of tho se who received dipyridamole, Adverse effects occurred in 78% of the a denosine study group and in 50% of the dipyridamole group (P<0.0001), Chest pain was the most common symptom with both drugs, Atrioventricul ar block occurred in 76 patients who received adenosine but in none wh o received dipyridamole, Because of adverse effects, 28% of patients w ho received dipyridamole required extra monitoring time (mean, 6 +/- 5 minutes beyond the standard protocol), Aminophylline was administered to 163 and 6 patients, respectively, in the dipyridamole and adenosin e study groups. Conclusion: Adenosine causes slightly greater systemic vasodilation than does dipyridamole, Adverse effects occur less often with dipyridamole but, in comparison with adenosine, are more difficu lt to manage and necessitate more monitoring time as well as fairly fr equent intravenous use of aminophylline for reversal.